Silver Nanoparticles to Increase Antibacterial Efficiency in Bandages

A Survey of WHO showed that the wound infections rates are 5 - 34% in the world. It is necessary to treat the wounds properly as it will cause more infection inside the skin. Usage of normal bandages for the treatment of wounds or infections can heal the outer surface of the skin that too by a slow process. Many researchers started investigating the different healing properties of plant based bandages. Silver nanoparticles are known for their efficient antibacterial properties. It has gained greater attention in the biomedical industries. In this study, the nanoparticles are synthesized by using environment friendly green synthesis method. Ceiba pentandra aqueous leaf extract was used as reducing and capping agent for the silver nanoparticle synthesis. It was then evenly coated on a bamboo fabric material and then assessed for its antibacterial activity by using quantitative method. It is less hazardous as no toxic chemicals are involved. The Antibacterial activity of silver nanoparticles combined with the plant extract will exhibit efficient wound healing properties. The Bandage layer can further be designed to form a completely plant based product.

Process Optimization of Silver Nanoparticle Synthesis and Its Application in Mercury Detection

Silver nanoparticles (AgNPs) have stable reactivity and excellent optical absorption properties. They can be applied in various industries, such as environmental protection, biochemical engineering, and analyte monitoring. However, synthesizing AgNPs and determining their appropriate dosage as a coloring substance are difficult tasks. In this study, to optimize the process of AgNP synthesis and obtain a simple detection method for trace mercury in the environment, we evaluate several factors—including the reagent addition sequence, reaction temperature, reaction time, the pH of the solution, and reagent concentration—considering the color intensity and purity of AgNPs as the reaction optimization criteria. The optimal process for AgNP synthesis is as follows: Mix 10 mM of silver nitrate with trisodium citrate in a hot water bath for 10 min; then, add 10 mM of sodium borohydride to produce the AgNPs and keep stirring for 2 h; finally, adjust the pH to 12 to obtain the most stable products. For AgNP-based mercury detection, the calibration curve of mercury over the concentration range of 0.1–2 ppb exhibits good linearity (R2 > 0.99). This study provides a stable and excellent AgNP synthesis technique that can improve various applications involving AgNP-mediated reactions and has the potential to be developed as an alternative to using expensive detection equipment and to be applied for the detection of mercury in food.

Silver Nanoparticle Synthesis Using an Inkjet Mixing System

Individual nanoscale silver particles were produced using an inkjet mixing system. First, the behaviors of colliding droplets were investigated to prepare to conduct the synthesis without splitting merged droplets. When small droplets collided, they merged to form droplets that stayed in a state of coalescence at a higher discharging velocity. In addition, by changing the orientation at the collision point, the droplet velocity could be increased. Then, silver nanoparticle synthesis was conducted under conditions that avoided droplet splitting. Smaller particles were produced by higher-velocity collisions for all the examined droplet sizes. When droplets were 50–100 μm, an average particle diameter of 2.5 nm was produced. In addition, when droplets of different sizes collided, they formed a continuous supply of precursor, which subsequently resulted in production of particles with uniform size.

Comparative Study of the Silver Nanoparticle Synthesis Ability and Antibacterial Activity of the Piper Betle L. and Piper Sarmentosum Roxb. Extracts

Piper betle (P. betle) and Piper sarmentosum (P. sarmentosum) are the two members of the Piper genus, have been reported to be rich in phytochemicals and essential oils, which showed strong reducing power, antibacterial, and antifungal activities. P. betle recently has been studied and applied in several commercial products in the antimicrobial respect, meanwhile its relatives, P. sarmentosum has been lesser-known in this field. In this study, the two Piper species—P. betle and P. sarmentosum were studied to compare their ability in silver nanoparticle synthesis and efficacy in antibacterial activity. P. betle and P. sarmentosum were extracted by distilled water at different temperatures and times. Subsequently, their total reducing capacity was determined by DPPH scavenging and Folin-Ciocalteu assays to choose the appropriate extraction conditions. The silver nanoparticle solutions prepared by the extracts of P. betle (Pb.ext) and P. sarmentosum (Ps.ext) were characterized by Dynamic light scattering (DLS), Zeta potential, UV-vis, and Fourier-transform infrared (FTIR) measurements. Finally, the antibacterial activity of the synthesized silver nanoparticle solutions was tested against Escherichia coli using the agar diffusion well–variant method. The Pb.ext showed stronger reducing power with higher total polyphenol content (~125 mg GAE/mL extract) and better DPPH activity (IC50~1.45%). Both the green synthesized silver nanoparticle solutions (Pb.AgNP and Ps.AgNP) performed significantly stronger antibacterial activity on Escherichia coli compared to their initial extracts. Antibacterial tests revealed that Ps.AgNP showed remarkably better growth inhibition activity as compared to Pb.AgNP. This study would contribute useful and important information to the development of antibacterial products based on green synthesized silver nanoparticles fabricated by the extracts of P. betle and P. sarmentosum.